The invention concerns a sliding bearing composite material with a metallic support layer, an optional porous carrier layer disposed thereon, and a lead-free sliding layer which forms a sliding surface for a sliding partner, having a sliding layer material on the basis of plastic, with PEEK and a lubricant in the form of zinc sulfide and/or barium sulfate.
A sliding bearing composite material of this type is disclosed in DE 36 01 569 A1. This reference mentions PEEK as one of several polymers, although none of the embodiments comprises PEEK. The document teaches the use of 5–40 vol % of zinc sulfide and/or barium sulfide in the sliding layer material to increase wear resistance. It mentions additives, such as glass fibers, glass beads, carbon fibers, ceramic fibers and aramide fibers to increase stability. All embodiments include glass fibers or glass beads.
DE 37 36 292 A1 discloses a sliding layer film which can be separately produced and which can be applied either directly onto a metallic support layer or via an intermediate layer which serves as bonding agent. Suitable materials for the sliding layer are fluorinated plastic, in particular PTFE, modified PTFE, polyimide, or PEEK. None of the embodiments comprises PEEK. In accordance with this document, one or more fillers may be added to the sliding layer to increase and/or improve the thermal conductivity and/or wear properties. In particular carbon, aluminium oxide, ceramic materials, glass, bronze, molybdenum disulfide or silicon carbide can be embedded, in dependence on the application.
Sliding bearings of sliding bearing composite materials comprising a sliding layer on the basis of plastic are widely used in technology for the broadest of reasons, i.e. with regard to the loading capacity, chemical resistance and/or temperature resistance. Thermoplastic materials are known and available which guarantee thermal stability only for operating temperatures of up to approximately 90° C., which include e.g. ABS, high-pressure polyethylene (HD-PE), PVC, polysulfone (PS) etc. There are also a number of so-called technical thermoplastic materials which are suitable for operating temperatures of up to approximately 150° C., such as e.g. POM, PET, PA.
The present invention concerns such sliding bearing composite materials which are suitable for use at continuous operating temperatures of more than 180° C. They should also have very good tribological properties and favorable characteristic mechanical values with regard to shapability as well as high resistance to chemicals. The sliding bearing composite materials must moreover be suited for manufacture in an industrial production process.
These objects are achieved by a sliding bearing composite material having the features of the independent claim.